We're running a Hyper-V server with several VMs running domains on it. Each server group has a typical Windows setup: an AD server and an RD server.
As we have added more domains on VMs (we have about 2 dozen on there now), we've noticed login times and performance seems to be slowing down. Yet, every resource we can measure on the Hyper-V host (CPU, memory, hard drive access) suggests the hardware is not the cause at all. Response times of VHDs are consistently < 4 ms. CPU speeds on each VM are consistently < 20%. Memory usage on the servers is consistently < 50%.
Are there any other tools or metrics we can use to diagnose where there may be a bottleneck with Hyper-V?